During the manufacture of semiconductor devices, the manufactured semiconductor devices are subjected to a battery of tests in order to ensure their suitability for use by the ultimate consumer. This testing process is performed using automated testing equipment (ATE). The ATE system is designed to test the devices (usually referred to as devices under test or DUTs) over a wide variety of conditions. The ATE system generally includes a tester, which performs the test on the devices, and a handler, which introduces the devices to and removes the devices from the tester. During the testing process, it is generally preferred to have the devices kept at a pre-determined temperature since the temperature affects the electrical properties of the devices being tested. Further, in order to test the devices at design temperatures to mimic design and operational conditions of the device, the tester needs to test the devices over a range of temperatures. As such, there is a need to control the temperature of the device during the testing process.
One solution used to control the temperature involves placing a heating unit between the device being tested and a liquid cooled heat sink. However, this solution does not allow for rapid response times for heating and cooling. In addition, the heating unit would have to be very thin to prevent an inordinate amount of shielding and interference with the cooling effect of the heat sink. As such, the heating unit needs to have a low thermal mass, which increases costs, and hinders the response times and the use of high wattage.
According to another solution, a liquid is disposed between the heating unit and the device so as to lower the thermal resistance therebetween. However, the liquid itself needs to evaporate after the testing without leaving any residue on the device. Additionally, the liquid needs to have a large temperature range for the testing. Thus, such liquids are difficult to find, making the use of the liquid impractical.
Further, proposed solutions include using thermal electric devices and heat exchangers. However, the thermal electric devices are not useful for high power densities and are unreliable in an industrial environment.
As such, the existing solutions to provide temperature control of a DUT are not able to control wide ranges of temperatures, have a fast response time, and also be stable and easy to control during the testing process.